Crop harvesting machine including retractable sensor fingers with adjustable ground pressure and header tilt control

ABSTRACT

A crop harvesting machine with a cutter bar on a header frame has a height control system which uses depending sensor fingers arranged in contact with the ground so as to measure a height of the cutter bar above the ground. The sensor fingers are controllably retractable under actuation from an operator in the cab or automatically in response to prescribed conditions being met. The actuator used in retracting the sensor fingers can also be used to adjustably control ground pressure of the sensor fingers in the deployed position of the sensor fingers engaging the ground. The header height is adjusted using laterally spaced apart hydraulic linkages which can be operated at different elevations relative to one another responsive to different height signals relating height of opposing ends of the header frame relative to the ground to also control tilt of the header relative to the harvester frame.

This application is a divisional of U.S. parent application Ser. No.15/471,475, filed Mar. 28, 2017.

FIELD OF THE INVENTION

This invention relates to a crop harvesting machine including a tractorand a header with cutter bar that has a height control system which usesdepending sensor fingers arranged in contact with the ground so as tomeasure a height of the cutter bar above the ground carrying a crop tobe harvested, in which the sensor fingers are controllably retractableand in which the ground pressure of the sensor fingers can be adjustedwhen deployed. The height control system is particularly but notexclusively suited for a swather tractor, which simply carries theheader to form a swath, as the swather tractor has a lifting arrangementfor raising and lowering the cutter bar that is more limited in itsvertical height range and a drive system that provides highermanoeuverability than that of a combine harvester. The present inventionfurther relates to a crop harvesting machine having lateral spaced aparthydraulic linkages for controlling header height which can also beoperated independently of one another to tilt the header relative to theharvester frame.

BACKGROUND

A crop harvesting machine generally includes a crop header for cutting astanding crop including a header frame, a cutter sickle extending acrossa front cutter bar of the header frame for cutting the crop, and atransport system operable to transport the crop to a central dischargeopening of the header so as to form a swath.

The machine further includes a tractor or other vehicle for carrying theheader including a tractor frame having a first end and a second end,ground wheels for supporting the tractor in movement across the groundincluding a pair of transversely spaced first wheels at the first end, amounting assembly at the first end of the tractor frame for supportingthe header, and a lift linkage for raising and lowering the mountingassembly.

The crop header generally includes a header frame, an elongate cutterbar along a front edge of the frame including a cutter bar beam whichcarries a plurality of knife guards for guiding reciprocating movementof a sickle knife across a front edge of the cutter bar. When the cropheader is of the draper header type, then on the header is also mountedrearwardly of the cutter bar a draper assembly including a first andsecond draper guide roller each arranged at a respective end of thedraper assembly spaced apart along the cutter bar with an axis of eachroller extending substantially at right angles to the cutter bar, adraper forming a continuous loop of flexible material wrapped around therollers so as to define a front edge of the draper adjacent the cutterbar, a rear edge of the draper spaced rearwardly of the cutter bar, anupper run of the draper on top of the roller and a lower run of thedraper below the rollers. The cut crop thus falls rearwardly onto theupper run of the draper and is transported longitudinally of the header.

The draper header type can be used simply for forming a swath in whichcase the material is carried to a discharge opening of the header anddeposited therefrom onto the ground. Headers of this type can also beused for feeding a combine harvester so that the materials are carriedto an adapter member positioned at the discharge opening of the headerfor carrying the materials from the discharge opening into the feederhousing of the combine harvester. Yet further, headers of this type canbe used for hay conditioners in which the material from the dischargeopening is carried into crushing rolls. It will be appreciated,therefore, that the use of the header is not limited to particular typesof agricultural machine but can be used with any such machine in whichit is necessary to cut a standing crop and to transport that crop whencut longitudinally of the header for operation thereon.

These crop headers may employ a height control system so as to regulatea height of the cutter bar above the ground, which allows for as much ifnot all of the standing crop to be harvested particularly when the cropis growing on uneven terrain.

Conventional height control systems use a sensor finger which ispositioned so as to extend downwardly from the header frame to theground to determine the above ground height of the cutter bar byphysical contact of the finger therewith. In view of the ground contactof the sensor fingers suited for following the ground in a forwardcutting direction, the sensor fingers are readily susceptible to damageunder a variety of instances when the harvester is displaced across theground in directions other than the conventional forward cuttingdirection. Furthermore, these systems typically include at least onespring arranged to bias the finger against the ground so that the fingerfollows same, however, adjusting the downward pressure of the sensorfinger when deployed involves a complex mechanical process of manuallyadjust the spring position.

United States Patent Application Publication No. 2017/0064904 by CNHIndustrial America LLC discloses one example of a harvester having aheight control feature. The method includes positioning the header to apredetermined cut height set point, measuring a ground speed of theagricultural harvester, measuring a height of the header relative to aground surface at a plurality of positions along a length of the header.The method further includes lowering the header towards a first adjustedcut height threshold if a measured height of one of the plurality ofpositions is above the predetermined cut height set point and themeasured ground speed is less than a first predetermined ground speed.The subject application allows the automatic header height controlsoftware on an agricultural harvester to automatically deviate from thepredetermined cut height set point. The height control is limited tocorrecting for ground forming a crown or a swale in the direction oftravel, but does not accommodate for laterally sloped terrain.

SUMMARY OF THE INVENTION

According to one aspect of the invention there is provided a cropharvesting machine comprising:

a harvester frame having longitudinally opposed first and second endssupported for movement across ground having a crop thereon to beharvested;

a drive system mounted on the harvester frame for propelling theharvester frame in one of a plurality of drive conditions across theground;

a cab mounted on the harvester frame for an operator;

a header mounted at the first end of the harvester frame comprising aheader frame with a main rear frame member and a plurality of forwardlyextending frame members each supported by the main rear frame member,and an elongate cutter bar connected to the forward end of the forwardlyextending frame members so as to be arranged along a front edge of theheader frame for cutting the crop;

a height control system for controlling a height of the header relativeto the ground, the height control system comprising:

-   -   a sensor assembly arranged to determine height of the cutter bar        above the ground, the sensor assembly including (i) a sensor        finger which is elongate between a top portion of the finger        pivotally supported on the header and a bottom portion of the        finger distal from the top portion such that the sensor finger        is movable between a working position in which the finger        depends from the top portion below the header frame to the        bottom portion of the finger which is spaced below the header        frame for engaging the ground and following contours of the        ground and a raised position in which said bottom portion of the        sensor finger is in close proximity to the header frame and (ii)        a position sensor arranged to generate an output signal        corresponding to the height of the header relative to the ground        based upon a position of the sensor finger;    -   a lift linkage operable between the header frame and the        harvester frame to raise and lower the header frame relative to        the harvester frame responsive to the output signal of the        position sensor to position the cutter bar at a prescribed        height;

a controller arranged to generate a lift signal; and

a sensor positioning assembly operatively coupled to the controller soas to be arranged to lift the sensor finger from the working position tothe raised position responsive to the lift signal from the controller.

Thus, upon command from an operator, or upon detection of an operatingcondition of the header or the tractor during which it is possible forthe finger to become damaged, the sensor finger can be automaticallyretracted from the working position to the raised position in which thefinger is free from contact with the ground.

This is particularly suited for swather or windrower tractors which arehighly manoeuvrable and can be steered on the spot or reversed whilecutting which can impose damaging loads on the sensor fingers whichtypically only tolerate deflection when moving in the working direction.However, this type of system may also be used with a combine harvesteras it may reduce need to lift the whole of the header frame so as toavoid damage to the sensor when re-positioning the crop harvestingmachine for example prior to further crop cutting.

In general therefore the arrangement as described in more detailhereinafter provides a sensor with a finger which is movable between aworking position and a raised position and is thus provided with a firstmechanism which deploys and biases the finger to the working positionagainst the ground and a second mechanism which opposes the biasingdirection of the first mechanism so that the finger can be retractedfrom the working position to the raised position upon detection ofparticular drive conditions of the tractor in which damage to the fingermay occur.

The sensor finger preferably includes a biasing member to bias thesensor finger towards one of the raised position and the workingposition and wherein the sensor positioning assembly includes anactuator operable to produce a biasing force acting against the biasingmember to position the sensor finger in the other one of the raisedposition and the working position in which the actuator is responsive tothe lift signal from the controller to displace the sensor finger fromthe working position to the raised position. In the illustratedembodiment, the biasing member acts to urge the sensor finger towardsthe raised position and the actuator acts to urge the sensor fingertowards the working position.

According to another important independent aspect of the invention, thesensor positioning assembly includes an actuator operable in the workingposition to control a downward pressure of the sensor finger on theground according to a set point pressure within a range of downwardpressures in which the set point pressure is controllably adjustable bythe controller. Preferably, the set point pressure is automaticallycontrolled by the controller responsive to a height of the header frame.

In the illustrated embodiment, the actuator of the sensor positioningassembly is a hydraulic actuator and the downward pressure is controlledby using the controller to control a hydraulic pressure supplied to theactuator from a hydraulic supply on the harvester frame.

The hydraulic supply may be operable to vary the prescribed pressuresupplied to the actuator throughout of range of pressures in the workingposition to maintain engagement of the sensor finger with the groundthrough a range of heights of the header frame relative to the ground.

The controller may be further arranged to reduce the prescribe pressuresupplied by the hydraulic supply to the actuator to a reduced pressurecorresponding to a force applied to the sensor finger by the actuatorbeing exceeded by a force applied to the sensor finger by the spring forraising the sensor finger to the raised position

The controller may include a sensor lifting criterion stored thereon inwhich the controller is arranged to generate the lift signal when aprescribed operating condition of the crop harvesting machine meets thesensor lifting criterion.

The sensor lifting criterion may include (i) a non-cutting position ofthe header such that the controller is arranged to generate the liftsignal when the header is lifted out of a cutting position of theheader, (ii) a reverse travel criterion such that the controller isarranged to generate the lift signal when the harvester frame isoperated in a reverse direction opposite to a normal forward directionfor cutting crop, in which the controller may be operatively coupled toan operative drive selector in the operator cab to determine theoperating condition and if the reverse travel criterion has been met, or(iii) a turning criterion corresponding to a turning radius of theharvester frame exceeding a turning radius limit, in which thecontroller may be operatively coupled to the drive system so as to bearranged to measure relative wheel speed between laterally opposed drivewheels on the harvester frame to determine the turning radius of theharvester frame if the turning criterion has been met, or (iv) anycombination of the above.

The sensor finger is preferably contained within a lower boundary of theheader frame in the raised position, for example so that the bottomportion of the sensor finger is supported at or above a bottom side ofthe beams in the raised position.

According to another important independent aspect of the presentinvention, when the sensor finger is pivotal between the workingposition and the raised position about a finger pivot axis, the cropharvesting machine may further comprise a resilient bushing pivotallysupporting the sensor finger relative to the header frame such that thesensor finger can be angularly deflected relative to the finger pivotaxis.

Preferably, the crop harvesting machine comprises a plurality of sensorassemblies at spaced apart positions across the header frame and asensor positioning assembly associated with each sensor assembly whichis responsive to said controller.

According to another important independent aspect of the presentinvention there is provided a crop harvesting machine comprising:

a harvester frame having longitudinally opposed first and second endssupported for movement across ground having a crop thereon to beharvested;

a drive system mounted on the harvester frame for propelling theharvester frame in one of a plurality of drive conditions across theground;

a cab mounted on the harvester frame for an operator;

a header mounted at the first end of the harvester frame comprising aheader frame with a main rear frame member and a plurality of forwardlyextending frame members each supported by the main rear frame member,and an elongate cutter bar connected to the forward end of the forwardlyextending frame members so as to be arranged along a front edge of theheader frame for cutting the crop;

a height control system for controlling a height of the header relativeto the ground, the height control system comprising:

-   -   a sensor assembly arranged to determine height of the cutter bar        above the ground, the sensor assembly including (i) a sensor        finger which is elongate between a top portion of the finger        pivotally supported on the header and a bottom portion of the        finger distal from the top portion such that the sensor finger        is movable between a working position in which the finger        depends from the top portion below the header frame to the        bottom portion of the finger which is spaced below the header        frame for engaging the ground and following contours of the        ground and a raised position in which said bottom portion of the        sensor finger is in close proximity to the header frame and (ii)        a position sensor arranged to generate an output signal        corresponding to the height of the header relative to the ground        based upon a position of the sensor finger;    -   a lift linkage operable between the header frame and the        harvester frame to raise and lower the header frame relative to        the harvester frame responsive to the output signal of the        position sensor to position the cutter bar at a prescribed        height; and

a sensor positioning assembly operatively coupled between the sensorfinger and the header including an actuator operable to control adownward pressure of the sensor finger on the ground according to a setpoint pressure within a range of downward pressures; and

a controller arranged to controllably adjust the set point pressure.

The set point pressure may be automatically controlled by the controllerresponsive to a height of the header frame, and/or may be controllableby an operator control in the cab.

The sensor positioning assembly in this instance may also include abiasing member to bias the sensor finger towards one of the raisedposition and the working position and an actuator operable to produce abiasing force acting against the biasing member to position the sensorfinger in another one of the raised position and the working position inwhich the actuator is responsive to the lift signal from the controllerto displace the sensor finger from the working position to the raisedposition.

According to another important independent aspect of the presentinvention there is provided a crop harvesting machine comprising:

a harvester frame supported for movement across ground having a cropthereon to be harvested;

a cab mounted on the harvester frame for an operator;

a header mounted on the harvester frame comprising a header frame and anelongate cutter bar connected to the forward end of the forwardlyextending frame members so as to be arranged along a front edge of theheader frame for cutting the crop;

a drive system mounted on the harvester frame for propelling theharvester frame across the ground in a forward working direction whencutting crop;

a height control system for controlling a height of the header relativeto the ground, the height control system comprising:

-   -   a first lift linkage and a second lift linkage operatively        connected between the harvester frame and the header frame at        laterally spaced apart positions so as to be associated with        laterally opposed first and second side portions of the header        frame respectively;    -   at least one first height sensor associated with the first side        portion of the header frame so as to be arranged to generate a        first height signal representative of a respective height of the        first side portion of the header frame above the ground;    -   at least one second height sensor associated with the second        side portion of the header frame so as to be arranged to        generate a second height signal representative of a respective        height of the second side portion of the header frame above the        ground;    -   a height controller operatively connected to the height sensors        and the first and second lift linkages so as to be arranged to        operate the first and second lift linkages at different        elevations relative to one another responsive to the first        height signal and the second height signal such that the header        frame is controllably tiltable relative to the harvester frame        about a tilt axis oriented in the forward working direction.

The height sensors according to this aspect of the invention maycomprise any suitable mechanism for measuring height of the headerrelative to the ground, including sensor fingers according to thepreferred embodiment described herein, or alternatively ultrasoundsensors, radar sensors, or optical sensors, and the like.

In some embodiments, the height controller may be arranged toindependently adjust each lift linkage responsive to the respectiveheight signal that is associated with that side portion of the headerframe deviating from a prescribed height.

Alternatively, the height controller may be arranged to proportionallyadjust the first and second lift linkages relative to one anotherresponsive to a difference between the first height signal and thesecond height signal exceeding a prescribed threshold.

The height controller is preferably also arranged to adjust both liftlinkages in the same direction to adjust an overall height of the headerframe relative to the harvester frame responsive to a combined height ofthe first and second height signals deviating from a prescribed height.

In each instance, the prescribed height is preferably stored on theheight controller and the prescribed height is adjustable using operatorcontrols in the cab.

In another embodiment, said at least one first height sensor maycomprise two first height sensors at laterally spaced apart positionsalong the first side portion of the header frame and said at least onesecond height sensor may comprise two second height sensors at laterallyspaced part positions along the second side portion of the header frame,in which the height controller is arranged to operate the first andsecond lift linkages so as to optimize the height signal from each ofthe height sensors to the prescribed height.

The height controller may be further arranged to operate the first andsecond lift linkages so as to maintain a minimum header height at eachof the height sensor locations.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

FIG. 1 is a perspective view of a crop harvesting machine including aheader supporting a plurality of sensor assemblies of a height controlsystem thereon;

FIG. 2 is a top plan view of the crop harvesting machine according toFIG. 1;

FIG. 3 is an end elevational view of the header of the crop harvestingmachine according to FIG. 1 in a working position of the height controlsystem;

FIG. 4 is an end elevational view of the header of the crop harvestingmachine according to FIG. 1 in a raised position of the height controlsystem;

FIG. 5 illustrates in elevational view one of the sensor assemblies ofthe height control system in a working position;

FIG. 6 illustrates in elevational view one of the sensor assemblies ofthe height control system in a raised position;

FIG. 7 is a perspective view of one of the sensor assemblies of theheight control system; and

FIG. 8 is a top plan view of the crop harvesting machine according toFIG. 1 including components of the height control system representedschematically thereon.

In the drawings like characters of reference indicate correspondingparts in the different figures.

DETAILED DESCRIPTION

The following description relates only those parts of the header andtractor which are of importance to the present invention and theremaining parts of the header including the frame structure, drives,ground wheels and the like are omitted as these will be well known toone skilled in the art.

There is illustrated in the accompanying drawings a crop harvestingmachine including tractor 10 and a header 23 for harvesting a crop.

A swather tractor which is indicated at 10 includes a frame 11 which iscarried on a first pair of driven ground wheels 12 and 13 and on asecond pair of non-driven castor wheels 14 and 15 so that the frame issupported for movement across the ground. The driven wheels 12 and 13are mounted on suitable supports 16 which support the ground wheelsrelative to the frame 11. The driven ground wheels 12 and 13 are eachdriven by a hydraulic motor 17 carried on the support 16 which receiveshydraulic fluid under pressure from a supply line and drives the groundwheel at a rate of rotation dependent upon the rate of flow of thehydraulic fluid. As such there is formed a drive system of the tractorfor propelling the crop harvesting machine across the ground carryingthe crop to be harvested. The swather tractor 10 is operable in aharvesting mode and in a transport mode. In the harvesting mode, it isnormally driven in a forward working direction M1 with a cab 30 orientedas shown in FIG. 1 so that the driver is overlooking a header 23 mountedon the tractor during normal forward movement for cutting a crop. Theswather tractor can also operate in a reverse direction in theharvesting mode. In the transport mode, the cab 30 is oriented so thatthe driver is overlooking an engine 24 of the tractor so that thetractor is well suited to be driven in an opposing transport directioncorresponding to direction of arrow M2, that is opposite to the forwardworking direction for cutting crop in the harvesting mode.

The wheels 14 and 15 are mounted on conventional castors 18 which swivelabout a castor pin 19. The ground wheels 14 and 15 are non-driven andare simply mounted in a supporting bracket 20 which can pivot around thecastor pin 19 so that the castor wheels follow the movement of thevehicle as controlled by the driven wheels 12 and 13. Thus the speed ofthe vehicle over the ground is controlled by the rate of rotation of thewheels 12 and 13 and steering is controlled by a differential in speedbetween the wheels 12 and 13.

The drive system is operable to drive the tractor frame according tovarious drive conditions. The drive conditions include driving in thenormal forward direction M1 in the normal harvesting configuration or inan opposing rearward direction M2 when the operator within the cabselects the rearward direction using the drive selector for reversingthe tractor in the harvesting mode, or alternatively for movingforwardly in the direction M2 that the operator faces in the transportmode.

The header frame is shown only schematically since this can vary widelyin accordance with requirements as is well known to a person skilled inthis art. At the driven end 11A of the frame is mounted a firsthydraulic height control linkage 21 and a second hydraulic heightcontrol linkage 22 at laterally spaced apart positions for carrying theheader 23 at an adjustable height relative to the frame. Each of theheight control linkages 21 and 22 comprises a mechanical linkage 200,for example a pair of parallel links pivotally coupled between theheader frame and the tractor frame, and a hydraulic linear actuator 202operatively connected between the header frame and the tractor frame tocontrol pivotal movement of the mechanical linkage as the actuator isextended and retracted to raise or lower the header frame and the cutterbar on the header frame relative to the tractor frame. These elementsare well known to persons skilled in this art and various differentdesigns can be used and accordingly, the height control linkages 21, 22are shown only schematically. In some embodiments, the pivotalconnections of the mechanical linkages 200 of the height controllinkages 21 and 22 are further configured to allow some relative flexingof the header about a tilt axis oriented in the forward cuttingdirection of the header as described in further detail below.

Various different types of headers can be used including disc typecutters or sickle knife cutters. The width of the header in the lateraldirection can vary considerably depending upon the type of crop and thecutting system employed. The header is preferably carried on the heightcontrol linkages 21, 22 of the tractor which are operable to raise andlower the header on the tractor between different working positions andbetween working positions and a raised position cleared from the groundfor moving the header over the ground when not in working position.

The tractor includes the engine 24 carried on the frame 11 adjacent asecond end 11B of the frame. The engine is arranged to drive a series ofhydraulic pumps 25, 26 and 27 for generating pressurized hydraulic fluidof a hydraulic fluid supply system of the tractor for driving thevarious components of the tractor as described hereinafter. Separatepumps can be used as shown or single pump can be used with the hydraulicfluid under pressure generated thereby being separated into separatecontrolled fluid paths for operating the various components.

The hydraulic fluid supply system 25, 26, and 27 of the tractor includesa pressure regulated output 100 which includes a pressure reducing andpressure relieving valve for outputting hydraulic fluid at a prescribedpressure for use by some of the components of the tractor as describedin further detail below. The magnitude of the prescribed pressure can beadjusted by an operator of the tractor using suitable hydraulic controlsin the cab of the tractor.

At the driven end 11A of the frame is provided the cab 30 which sitsover the driven end between the driven wheels 12 and 13 so the operatorcan look over the header during the cutting action on the field. The cab30 encloses an operator console generally indicated at 31 which includesa seat 32, a steering control 33 in the form of a conventional steeringwheel, a speed and drive control 34 and an accessory control 35.

The header 23 includes an elongate header frame 23B defined by a mainbeam 23C and forwardly extending legs 23D which carry a cutter bar 23A.

The header 23 comprises an elongate header frame 40, a rear supportframe structure 40B and a plurality of beams 40A extending horizontallyand forwardly from the rear support frame structure 40B to a cutter bargenerally indicated at 40C for support of that cutter bar across thefront of the header. The plurality of forwardly extending frame membersor beams 40A are arranged at spaced positions along the length of theheader frame so as to support the cutter bar 40C as an elongatestructure across the front edge of the header. The cutter extendslongitudinally along the front cutter bar of the header frame forcutting the crop when the header is moved in the forward workingdirection at M1 generally at a right angle to its longitudinal directionL. Different types of cutter bars can be used but the typical examplecomprises a sickle knife. A crop transport system 40F, generally drapersbut other systems can be used, is provided for transporting the croplongitudinally of the header to a central discharge opening 40G of theheader so as to form a swath to be deposited on the ground between thewheels 12, 13 of the tractor.

The cutter bar comprises a generally Y-shaped beam 42 with a leg and twobranches. The lower branch 42D forms a rearwardly and downwardlyextending wall which acts as a skid plate when the cutter bar is cuttingon the ground. The plate may be covered by a protective plastics wearshield (not shown).

A height control system is provided in conjunction with the liftlinkages 21, 22 in which the height control system comprises a pluralityof sensor assemblies 52 so that the cutter bar 42 may be maintained at aprescribed height relative to the ground so as to cut the crop. Thistype of system is particularly useful when the ground carrying the cropis uneven so that the height of the cutter bar may be adjusted so that auniform height of crop is harvested.

The sensor assemblies 52 of the height control system are spaced fromone another longitudinally of the header, across a width of the tractorframe. Each sensor assembly 52 forms a finger 55 elongated from a topend 56A pivotally attached via bracket 58 at the header frame 41,specifically to the cutter bar 40C at the bottom branch 42D, to atrailing bottom portion 56B distal from the top end and forming aterminus of the finger opposite the top end.

The finger is positionable in a working position so as to extend belowthe header frame at a downward and rearward slope relative to theforward cutting direction, with its bottom portion 56B in spacedrelation to the header frame at a position in contact with the ground,and in a raised position wherein the bottom portion is spaced upwardlyfrom the ground and upwardly relative to the working position so as tobe free of contact with the ground. More particularly, in the raisedposition, the bottom portion 56B is located in close proximity to theheader frame so as to be generally contained above a lower boundary ofthe header frame. That is, in the raised position the bottom portion 56Bof the finger is located at or above bottom surfaces 41 of the forwardlyextending beams 40A.

In the illustrated arrangement, the finger 55 is formed from rigidtubular material which is curved to be convex at the leading side whenmoving in the forward harvesting direction of the header frame so thatthe finger follows an arcuate path from its top end 56A to the bottomportion 56B. At the bottom portion 56B there is defined an end portion56D which is deflected rearwardly and upwardly relative to a remainderof the body of the finger to maintain a convex arcuate leading surfacefor sliding movement across the ground.

The finger 55 is pivotal between the working position and the raisedposition about a shaft 59 supported at the bracket 58 defining a pivotaxis of the finger. The shaft is oriented generally longitudinally ofthe header so that the elongate finger is oriented longitudinally of thetractor thereby being arranged to lie in a vertical plane parallel tothe forward working direction M1 of the tractor in a normal workingposition.

A collar 70 is provided at the top end 56A of the finger which isrotatably supported about the shaft 59 to rotate with the fingersupported thereon. A sleeve-shaped rubber bushing 69 surrounds the shaft59 at the location of the collar of the finger such that the bushing isreceived between the collar of the finger and the shaft. In thisinstance, the finger is biased to a neutral position in the lateraldirection to remain pivotal between working and raised positions withina plane of rotation perpendicular to the shaft, however, the finger canbe angular deflected away from the neutral position so as to be offsetfrom the pivot axis defined by the shaft within a range of offset anglesby deforming the bushing. This allows the finger to be deflectablerelative to the shaft in directions transverse of the finger, or inother words directions generally parallel to the shaft, where suchdeflection may occur for example upon sharp turning of the tractoroperating in the harvesting mode when moving generally in the forwardworking direction.

In a normal working position, the bottom portion 56B of the finger isarranged below the cutter bar at the ground so that the finger 55follows a contour of the ground, and an angular position of the fingerwith respect to the shaft is measurable with an appropriate positionsensor, for example a transducer 71, to determine a present height ofthe cutter bar above the ground. The position sensor thus generates anoutput signal corresponding to the height of the header relative to theground based upon a position of the sensor finger.

According to this output signal generated by the transducers of theposition sensors, a height controller 204, which receives the outputsignals from the height sensors, controls the operation of valves andhydraulic meters between the hydraulic supply 100 and the hydraulicactuators 202 of the linkages 21 and 22 to adjust the position of thehydraulic actuators and the resulting height of the header relative tothe ground. The height controller is a computer device which includes aprocessor for executing programming stored on a memory of the controllerto perform the various functions of the controller described herein.Typically, the height controller operates the hydraulic actuators 202 ofthe linkages 21 and 22 responsive to the output signals from the heightsensors if the measured heights differ from a prescribed height so as tomaintain the cutter bar height at that prescribed height. The prescribedheight is a stored value on the controller that can be readily adjustedby the operator using operator controls within the cab.

More particularly, the header frame includes a first side portionextending laterally outwardly beyond the first hydraulic lift linkage21, and a second side portion extending laterally outwardly opposite tothe first side portion beyond the second hydraulic lift linkage 22 suchthat the respective height of the first and second side portions of theheader frame can be independently controlled by adjusting the positionof the first and second hydraulic lift linkages respectively. The heightsensors 52 in this instance are all laterally spaced apart from oneanother along the header frame to include (i) a first outer sensor 52Aadjacent the first end of the header frame, (ii) a first inner sensor52B at an intermediate location along the first side portion between thefirst hydraulic lift linkage 21 and the first outer sensor 52A, (iii) asecond outer sensor 52D adjacent the second end of the header frame, and(iv) a second inner sensor 52C at an intermediate location along thesecond side portion between the second hydraulic lift linkage 22 and thesecond outer sensor 52D.

In one mode of operation of the height controller, when it is desirableto only control overall height of the header frame, the height signalsfrom all of the height sensors are collectively received by the heightcontroller 204, and the height controller simultaneously operates bothhydraulic lift linkages 21 and 22 always in the same direction by thesame amount together to simultaneously raise or simultaneously lower thelift linkages to raise or lower the overall header frame relative to theharvester frame while maintaining a generally horizontal and parallelorientation of the header frame relative to the harvester frame. In thisinstance, all of the height signals are combined to determine arepresentative height of the overall header frame, for example byaveraging the height signals, and the hydraulic lift linkages 21 and 22are operated to raise or lower the overall header frame if therepresentative height is either below or above the prescribed heightstored on the height controller respectively. Additional criteria may beemployed such as maintaining a minimum height at each sensor location,or by only adjusting the lift linkages if the representative heightdiffers from the prescribed height by an amount which exceeds apermissible threshold amount.

In a further mode of operation of the height controller, the overallheight of the header frame and an angular orientation of the headerframe about a tilt axis oriented in the forward working direction can becontrolled. In this instance the height controller can operate the firstand second hydraulic lift linkages at different elevations relative toone another responsive to height signals from the first height sensors52A and 52B and the second height sensors 52C and 52D respectively suchthat the header frame is controllably tiltable relative to the harvesterframe about the tilt axis in addition to the overall height beingcontroller.

More particularly, the height signals from both first sensors associatedwith the first side portion of the header frame are combined todetermine a first representative height associated with the first sideportion of the header frame, while the height signals from both secondsensors associated with the second side portion of the header frame arecombined to determine a second representative height associated with thesecond side portion of the header frame. Each representative heightdetermined by the height controller may be an average of the two heightsignals, a weighted average of the two height signals proportional tothe lateral distance from the tilt axis, or any other suitable means ofgenerating a height which is representative of an overall side portionof the header frame as opposed to a single location on the header frame.

In a preferred embodiment, the height controller operates a primaryvalve 206 which supplies hydraulic fluid to both lift linkages 21 and 22to control an overall elevation or height of both linkages and thus theoverall height of the header frame relative to the harvester frame andthe ground. In this manner, the height controller is arranged to adjustboth lift linkages in the same direction to adjust an overall height ofthe header frame relative to the harvester frame responsive to acombined height of the first and second height signals deviating from aprescribed height. In one embodiment, increasing the overall supply offluid will extend both actuators 202 of the linkages 21 and 22 to raiseboth linkages and raise the overall header, whereas decreasing theoverall supply of fluid will retract both actuators 202 of the linkages21 and 22 to lower both linkages and lower the overall header.

The height controller also operates a hydraulic meter 208 that functionsas a proportional control between the supply of hydraulic fluid from theprimary valve 206 to each of the lift linkages 21 and 22. In a neutralposition, hydraulic fluid is supplied equally to both lift linkages tomaintain a horizontal and parallel orientation of the header framerelative to the harvester frame and the ground; however, the heightcontroller is arranged to proportionally adjust the supply of hydraulicfluid to the first and second lift linkages relative to one anotherresponsive to a difference between the first height signal and thesecond height signal exceeding a prescribed threshold. In one example,if the height of the first side portion of the header frame exceeds theheight of the second side portion of the header frame by the prescribedthreshold amount, the height controller proportionally adjusts the flowof hydraulic fluid according to a first deviated position so that thefirst linkage is lowered and the second linkage is raisedsimultaneously. Alternatively, if the height of the second side portionof the header frame exceeds the height of the first side portion of theheader frame by the prescribed threshold amount, the height controllerproportionally adjusts the flow of hydraulic fluid according to a seconddeviated position so that the second linkage is lowered and the firstlinkage is raised simultaneously. The proportional adjustment thusmaintains the overall height of the header frame relative to theharvester frame, but will function to tilt the header frame relative tothe harvester frame about the tilt axis that is oriented in the forwardworking direction.

In another embodiment, the height controller may operate each liftlinkage independently of the other linkage. In this instance, the heightcontroller may adjust the first hydraulic lift linkage 21 responsive toa first representative height associated with the first side portion ofthe header frame which deviates from the prescribed height set by theoperator. Accordingly, a representative height below the prescribedheight will result in operating the lift linkage 21 to raise thecorresponding first side portion of the header frame, and operating thelift linkage to lower the first side portion of the header frame if itis above the prescribed height. Likewise, the height controller willadjust the second hydraulic lift linkage 22 responsive to a secondrepresentative height associated with the second side portion of theheader frame which deviates from the prescribed height set by theoperator such that a representative height below the prescribed heightwill result in operating the lift linkage to raise the correspondingsecond side portion of the frame, and operating the lift linkage tolower the second side portion of the header frame if it is above theprescribed height.

The height controller may also be operated to ensure various additionalcriteria are met such as maintaining a minimum header height at each ofthe height sensor locations. Furthermore, the height controller may bearranged such that no adjustments are made unless a deviation of therepresentative height determined by the sensors from the prescribedheight exceeds a minimum threshold for applying a correction. Ingeneral, the controller is configured to operate in any suitable mannerresulting in the lift linkages 21 and 22 being able to be controlled atdifferent elevations so as to collectively optimize in real-time theheight signal generated by each of the height sensors to be as close aspossible to the prescribed height, thereby resulting in adjustment ofboth angular orientation about the tilt axis and the overall height ofthe header frame relative to the harvester frame and relative to theground.

To control the positioning of the finger between the working and raisedpositions, a sensor positioning assembly is provided including (i) ahydraulic actuator 62 operable to lower the finger towards the workingposition in the direction D1 when actuated with increasing hydraulicpressure for maintaining the finger in the working position engaged withthe ground at a substantially even ground pressure as the ground variesin contour in use, and (ii) a spring 67 to provide an opposing bias tothe finger acting upwardly in direction D2 against the actuator 62 andtowards the raised position. Thus, the actuator 62 and the spring 67 areoperated in opposition to one another but as an overall system whichachieves positioning of the sensor finger in the desired position bycontrolling pressure within the actuator 62.

In alternative embodiments, the spring 67 make take various forms ofbiasing elements including for example elastomer torsion elements, or ahydraulic pressure via a double acting cylinder functioning as theactuator 62 in one instance or a second single acting cylinder inaddition to the single acting cylinder of the actuator 62 in anotherinstance. In yet further arrangements, the biasing element and theactuator could be reversed so that the biasing force which retracts thesensor fingers is a controlled hydraulic pressure of the actuator andthe downward force is provided by a biasing element such as the spring.

According to the illustrated embodiment, to control the pressure of theactuator 62, the actuator 62 is coupled to the pressure regulated output100 of the hydraulic supply system of the tractor and the sensorpositioning assembly includes a sensor controller 80 for (i) determiningwhen to raise and lower the finger between the working position and theraised position based on sensor lifting criteria stored on thecontroller, and (ii) adjusting the prescribed pressure output by thehydraulic supply system to the actuator in order to accomplish raisedand lowering of the sensor finger. The sensor controller is a computerdevice which includes a processor for executing programming stored on amemory of the controller to perform the various functions of thecontroller described herein.

The spring 67 in the illustrated embodiment is a helical spring mountedcoaxially about the shaft 59 of the finger and is operatively connectedbetween the header frame and the finger to provide a torsional bias tothe finger and bias the finger in the direction D2.

The hydraulic actuator 62 is a piston cylinder type actuator which ispivotally mounted at a top cylinder end thereof 63A at a location spacedrearwardly from the pivotal connection at the top end of the finger onthe bracket 58 at a fixed location relative to the header frame. Thebottom piston end 63B of the actuator 62 is pivotally connected at arear side of the finger to an intermediate location therealong betweenthe top end 56A and the bottom portion 56B, spaced from the pivot axisof the finger.

The hydraulic actuator 62 is a single acting cylinder which is operatedby pumping fluid through supply lines into its chamber to extend thepiston rod 64 when pressure of the supplied hydraulic fluid is increasedthereby acting to displace the finger 55 downwardly towards the workingposition. In this manner, the actuator biases the finger in a directionD1 to deploy the finger into the working position. The actuator is thusalso usable to apply various amounts of downward pressure to hold thebottom portion of the finger against the ground.

In a normal operating condition for cutting crop in the forward workingdirection of the harvesting mode, when it is desirable for the sensorfingers to be deployed in the working position, the prescribed pressureof hydraulic fluid supplied to the actuator 62 corresponds to a pressurewhich is sufficient to generate a downward biasing force or biasingtorque acting on the finger which exceeds the upward biasing torqueacting on the sensor finger by the spring 67. The amount of excessbiasing torque provided by the hydraulic actuator 62 relative to thespring 67 determines the downward pressure of the sensor finger on theground.

Operator controls which are accessible by the operator within the cabmay be provided to allow the operator to adjust the prescribed pressurefor operating in the normal operating condition which effectivelyadjusts the downward pressure of the sensor fingers on the ground. Inthis manner, the operator can make accommodations for different groundconditions, for example wet or dry conditions, or different types ofcrops overlying the ground which can affect how closely the sensorfingers follow the contours of the ground.

The prescribed operating pressure of fluid supplied to the actuator 62can also be automatically controlled by the controller to vary accordingto the operating height of the cutter bar relative to the ground. Due tothe configuration of the linkage, a constant hydraulic fluid pressure atthe actuator 62 may result in different amounts of pressure of thebottom portion of the sensor finger against the ground throughout therange of movement of the sensor finger in the working positioncorresponding to different heights of the cutter bar relative to theground. To accommodate for this, the controller may vary the amount ofhydraulic fluid pressure provided to the actuator 62 proportionally tothe height of the cutter bar relative to the ground so as to maintain aconstant pressure of the bottom portion of the sensor fingers engagedupon the ground.

In this instance the sensor positioning assembly, which comprises theactuator 62 and the biasing spring, is operatively coupled between thesensor finger and the header such that the actuator is operable tocontrol a downward pressure of the sensor finger on the ground accordingto a set point pressure within a range of downward pressures, and thecontroller is arranged to controllably adjust the set point pressure.Preferably the set point pressure is automatically controlled by thecontroller responsive to a height of the header frame, however, theoperator may also manually adjust the downward pressure if desired. Whenthe actuator is a hydraulic actuator as described herein, the downwardpressure is controlled by using the controller to control the hydraulicpressure supplied to the actuator

The controller is also operable to determine when conditions arise whichmay cause damage to the sensor fingers if they remain in the deployedworking position. In order to accomplish this, several finger raisingcriteria are stored on the controller and compared to the currentoperating condition of the header or the tractor so that if any one ormore of the finger raising criteria are met, the controller will act togenerate a lift signal that the actuator is responsive to for loweringthe prescribed pressure of hydraulic fluid supplied to the actuator 62sufficiently to raise the sensor fingers into the raised positionthereof. More particularly, the prescribed pressure is lowered to alevel which corresponds to a downward force or biasing torque acting onthe sensor finger as a result of the actuator 62 which is exceeded bythe upward force or biasing torque acting on the sensor finger as aresult of the spring 67. In this manner, the spring force exceeds theforce provided by the actuator 62 to automatically retract the actuatorand raise the sensor finger into the raised position.

The various sensor raising criteria include a reverse travel criteriacorresponding to displacement of the harvester frame in a reversedirection opposite to a normal forward direction for cutting crop. Inorder to accomplish this, the controller is operatively coupled to theoperator drive selector 34 in the cab to determine the current drivecondition and thus determine if the reverse travel criteria and has beenmet. Alternatively, the condition of various components in the drivesystem which determine the direction of the drive wheel rotation can bemonitored to detect movement in the reverse direction M2.

The sensor raising criteria can also include a header position criterionsuch that a lift signal is generated by the controller to cause theactuators to respond and result in the sensor fingers being raised whenthe operator manually commands the header to be lifted out of thecutting position. The controller in this instance may be coupled to theheader position controls or to a header position sensor to determine ifthe header is in the cutting position or is raised into a non-cuttingposition.

The sensor raising criteria can also include a header drive criterionsuch that a lift signal is generated by the controller to cause theactuators to respond and result in the sensor fingers being raised whenthe header drive is disengaged, regardless of drive direction.

If desired, the sensor raising criteria can also include a transportmode criteria corresponding to displacement of the driver seat into thetransport mode facing rearwardly towards the engine 24, opposite to theforward working direction for cutting crop, regardless of the directionof movement of the swather tractor. By operatively coupling thecontroller to the drive selector or the operating position of theoperator seat, the controller can determine if the transport criteriahas been met. The transport mode is redundant and not required if aheader drive criterion is present as the sensors will always be raisedwhen the header drive is not engaged, and the header drive cannot beengaged when in the transport mode.

The sensor raising criteria can also include a turning criterioncorresponding to a turning radius of the harvester frame exceeding aturning radius limit. In this instance the controller can be operativelycoupled to the drive system, and more particularly the hydraulic motors17 of the two drive wheels, so as to be arranged to measure the wheelspeed of each wheel and calculate the relative wheel speed to estimatethe turning radius of the harvester frame. If the turning radius exceedsa corresponding turning radius limit, the turning criteria is determinedto have been met. Alternatively, the controller may be connected to asteering wheel sensor position or the like to determine the steeringangle which is compared to the turning criterion by the controller todetermine if the sensor fingers should be raised.

The sensor raising criteria can also include an override criterioncorresponding to an override switch in the operator cab being in anactive condition. The override switch could comprise a toggle switchoperable between an inactive condition in which the controller operatesautomatically according to remaining criteria to determine if the sensorfingers should be raised or not, or an active condition in which theoperator overrides the automatic control provided by the controller. Inthe active condition of the override switch, an override signal from theswitch to the controller will cause the controller to generate the liftsignal to raise the sensor fingers.

In addition to the criteria noted above, other criteria may be stored onthe controller which represent other operating conditions or the headeror the tractor where it is desirable for the sensor fingers to beraised. In either instance, if the controller determines that one ormore of the criteria has been met, the controller will lower theprescribed pressure of hydraulic fluid supplied to the actuator 62 tocause the sensor fingers to be raised under the greater biasing torqueprovided by the springs 67.

In either of the raised or working positions, the controller continuesto monitor if any one of the criteria is met. Accordingly, when thecorresponding criteria which may have triggered raising of the sensorfingers is no longer met, the controller will return the prescribedpressure supplied to the actuators 62 back to the normal operatingpressure which corresponds to a biasing torque provided by the actuator62 which exceeds the biasing torque of the spring to lower the sensorfingers back to the working position.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of samemade, it is intended that all matter contained in the accompanyingspecification shall be interpreted as illustrative only and not in alimiting sense.

1. A crop harvesting machine comprising: a harvester frame havinglongitudinally opposed first and second ends supported for movementacross ground having a crop thereon to be harvested; a drive systemmounted on the harvester frame for propelling the harvester frame in oneof a plurality of drive conditions across the ground; a cab mounted onthe harvester frame for an operator; a header mounted at the first endof the harvester frame comprising a header frame with a main rear framemember and a plurality of forwardly extending frame members eachsupported by the main rear frame member, and an elongate cutter barconnected to the forward end of the forwardly extending frame members soas to be arranged along a front edge of the header frame for cutting thecrop; a height control system for controlling a height of the headerrelative to the ground, the height control system comprising: a sensorassembly arranged to determine height of the cutter bar above theground, the sensor assembly including (i) a sensor finger which iselongate between a top portion of the finger pivotally supported on theheader and a bottom portion of the finger distal from the top portionwhich is operable in a working position in which the finger depends fromthe top portion below the header frame to the bottom portion of thefinger which is spaced below the header frame for engaging the groundand following contours of the ground and (ii) a position sensor arrangedto generate an output signal corresponding to the height of the headerrelative to the ground based upon a position of the sensor finger; alift linkage operable between the header frame and the harvester frameto raise and lower the header frame relative to the harvester frameresponsive to the output signal of the position sensor to position thecutter bar at a prescribed height; and a sensor positioning assemblyoperatively coupled between the sensor finger and the header includingan actuator operable to control a downward pressure of the sensor fingeron the ground according to a set point pressure within a range ofdownward pressures in the working position.
 2. The crop harvestingmachine according to claim 1 further comprising a controller arranged tocontrollably adjust the set point pressure.
 3. The crop harvestingmachine according to claim 2 wherein the set point pressure isautomatically controlled by the controller responsive to a height of theheader frame.
 4. The crop harvesting machine according to claim 1wherein the set point pressure is controllable by an operator control inthe cab.
 5. The crop harvesting machine according to claim 1 furthercomprising: the sensor finger being movable between the working positionand a raised position in which said bottom portion of the sensor fingeris in close proximity to the header frame; the sensor assembly includinga biasing member to bias the sensor finger towards one of the raisedposition and the working position, and the actuator being operable toproduce a biasing force acting against the biasing member to positionthe sensor finger in another one of the raised position and the workingposition
 6. The crop harvesting machine according to claim 5 wherein theactuator is responsive to a lift signal from the controller to displacethe sensor finger from the working position to the raised position. 7.The crop harvesting machine according claim 5 wherein the biasing memberacts to urge the sensor finger towards the raised position and theactuator acts to urge the sensor finger towards the working position. 8.The crop harvesting machine according to claim 1 wherein the actuator ofthe sensor positioning assembly is a hydraulic actuator and the downwardpressure is controlled by using a controller to control a hydraulicpressure supplied to the actuator from a hydraulic supply on theharvester frame.
 9. The crop harvesting machine according to claim 8wherein the hydraulic supply is operable to vary the prescribed pressuresupplied to the actuator throughout a range of pressures in the workingposition to maintain engagement of the sensor finger with the groundthrough a range of heights of the header frame relative to the ground.10. The crop harvesting machine according to claim 8 further comprising:a spring acting to urge the sensor finger towards a raised position; thehydraulic actuator acting to urge the sensor finger towards the workingposition; and the controller being arranged to reduce the prescribepressure supplied by the hydraulic supply to the actuator to a reducedpressure corresponding to a force applied to the sensor finger by theactuator being exceeded by a force applied to the sensor finger by thespring for raising the sensor finger to the raised position.
 11. A cropharvesting machine comprising: a harvester frame supported for movementacross ground having a crop thereon to be harvested; a cab mounted onthe harvester frame for an operator; a header mounted on the harvesterframe comprising a header frame and an elongate cutter bar connected tothe forward end of the forwardly extending frame members so as to bearranged along a front edge of the header frame for cutting the crop; adrive system mounted on the harvester frame for propelling the harvesterframe across the ground in a forward working direction when cuttingcrop; a height control system for controlling a height of the headerrelative to the ground, the height control system comprising: a firstlift linkage and a second lift linkage operatively connected between theharvester frame and the header frame at laterally spaced apart positionsso as to be associated with laterally opposed first and second sideportions of the header frame respectively; at least one first heightsensor associated with the first side portion of the header frame so asto be arranged to generate a first height signal representative of arespective height of the first side portion of the header frame abovethe ground; at least one second height sensor associated with the secondside portion of the header frame so as to be arranged to generate asecond height signal representative of a respective height of the secondside portion of the header frame above the ground; a height controlleroperatively connected to the height sensors and the first and secondlift linkages so as to be arranged to operate the first and second liftlinkages at different elevations relative to one another responsive tothe first height signal and the second height signal such that theheader frame is controllably tiltable relative to the harvester frameabout a tilt axis oriented in the forward working direction.
 12. Thecrop harvesting machine according to claim 11 wherein the heightcontroller is arranged to independently adjust each lift linkageresponsive to the respective height signal that is associated with thatside portion of the header frame deviating from a prescribed height. 13.The crop harvesting machine according to claim 12 wherein the prescribedheight is stored on the height controller and is adjustable usingoperator controls in the cab.
 14. The crop harvesting machine accordingto claim 11 wherein the height controller is arranged to proportionallyadjust the first and second lift linkages relative to one anotherresponsive to a difference between the first height signal and thesecond height signal exceeding a prescribed threshold.
 15. The cropharvesting machine according to claim 14 wherein the height controlleris arranged to adjust both lift linkages in the same direction to adjustan overall height of the header frame relative to the harvester frameresponsive to a combined height of the first and second height signalsdeviating from a prescribed height.
 16. The crop harvesting machineaccording to claim 15 wherein the prescribed height is stored on theheight controller and the prescribed height is adjustable using operatorcontrols in the cab.
 17. The crop harvesting machine according to claim11 wherein said at least one first height sensor comprises two firstheight sensors at laterally spaced apart positions along the first sideportion of the header frame and said at least one second height sensorcomprises two second height sensors at laterally spaced part positionsalong the second side portion of the header frame, and wherein theheight controller is arranged to operate the first and second liftlinkages so as to optimize the height signal from each of the heightsensors to the prescribed height.
 18. The crop harvesting machineaccording to claim 11 wherein the height controller is arranged tooperate the first and second lift linkages so as to maintain a minimumheader height at each of the height sensor locations.